A control interrupt crosses from a fast sensor clock into a slower processing clock. The system runs for weeks, then freezes in an illegal control state that never reproduces on the bench. This topic works that generic, illustrative scenario end to end: what you are told, how you investigate, what the cause and fix are, and how to narrate it in an interview in under five minutes.
Lesson | After it you can... |
|---|---|
Repeat the symptom precisely without leaping to a cause. | |
Order the debug: crossing audit before theories, evidence before fixes. | |
Name the unsynchronised fanout cause and the legal synchroniser fix. | |
Tell the story in five minutes with the framework audible in every beat. |
No company or product names appear: practise generalising the story the same way, since interviewers score discretion as well as debugging.
The symptom with its rate: a rare illegal-state freeze that never reproduces. Everything in the investigation follows from rare plus unreproducible.